nrfjprog

An implementation of the Nordic "nrfjprog.exe" program using python and jlink.py.

nrfjprog.exe is used to program softdevices and application code in the nRF51422 and nRF51822 system-on-chip radio microcontrollers.

It uses the Segger "J-Link" hardware, or the built-in Segger supplied with many of the Nordic development kits and dongles.

Features

I mostly intend to support the subset of features that are needed to make the SDK Makefiles work on a Linux or OS X machine.

I ran the following on a selection of installed SDKs to see what nrfjprog options are used by the Makefiles:

grep nrfjprog -rI /opt/nrf51sdk-* | grep Makefile | sed s/.*nrfjprog/nrfjprog/ | sort | uniq

This gives the following set of uses:

nrfjprog --erase
nrfjprog --reset
nrfjprog --reset --program softdevice.hex
nrfjprog --reset --program $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).hex

So nrfjprog implements the --erase, --reset, and --program commands.

Setting up

There are two paths, lib32/ and lib64/. You must download the appropriate DLL from http://www.segger.com and add it to the appropriate directory depending on your system.

The DLL ending is different among the three supported platforms:

Platform	Extension
Windows	.dll
Linux	.so
OS X	.dylib

The Windows dll is named jlinkarm.dll.

The Linux dll is named something like libjlinkarm.so.4.62.1. After putting it in the right directory, make a symlink to libjlinkarm.so.4 in the same directory:

 ln -s libjlinkarm.so.4.*.* libjlinkarm.so.4

Linux users should also install the Segger-provided udev rule to allow the device to be used as a non-root user. See the Segger documentation.

The OS X dll is named something like libjlinkarm.4.62.1.dylib. After putting it in the right directory, make a symlink to libjlinkarm.4.dylib in the same directory:

 ln -s libjlinkarm.4.*.*.dylib libjlinkarm.4.dylib

To test that the DLL is functioning properly, connect a Segger and run python jlink.py by itself. It will error out if the library doesn't load or the Segger isn't connected.

Installation

Install by running "setup.py install". This will install the library and segger libs to a Python-findable location.

Usage

Consult the nrfjprog.exe documentation. If this nrfjprog behavior diverges from the official one, please file a bug.

Using Nordic SDK Makefiles

Here's a hint for using the Nordic Makefiles. They have a weirdly specific GCC installation path. Furthermore, this path is hardcoded in the SDK Makefile.common and cannot be overridden by application Makefiles.

Rather than horsing around with compiling GCC from scratch, or using lockin toolchain vendors, it is easier and better to use a distribution-supported GCC, or the ARM-unofficially-supported PPA (for Ubuntu achievers):

sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
sudo apt-get update
sudo apt-get install gcc-arm-none-eabi

A simple symlink will make things work fine with GCC in the normal location:

 sudo ln -rs /usr /usr/local/gcc-arm-none-eabi-4_8-2014q1

Now the Makefiles in the SDK will work unchanged, including the "make flash" target.